The present invention relates to an improved 35-mm photographic film.
35-mm photographic film in Japan is regulated in configuration by Japanese Industrial Standard K7519-1964, corresponding to U.S. American National Standard ANSI PH 1.14-1976. Also, the configuration of perforations which are formed along the sides thereof in the longitudinal direction is set forth in Japanese Industrial Standard K7552-1965, corresponding to ANSI PH 22.93-1980 and PH 22.139-1980. However, the types and properties of the film support are not regulated. Therefore, film manufacturers have provided various photographing films having different film supports. Most of these photographing films have a triacetate cellulose (TAC) base. However, TAC base 35-mm photographing film suffers from the following difficulties in handling or processing:
(i) In winding or rewinding the film in a camera, the perforations of the film may be broken by the film feeding pawl wherein film portions between the perforations may be torn out. If this occurs, the photographing operation must be stopped.
(ii) Film having such torn-out portions may be wound in the camera. However, when the film is conveyed by a roller conveyor type automatic developing machine to be processed in a developing laboratory, the film may tear in the widthwise direction thereof in the area of a torn-out portion. If this occurs, the film processing operation must be halted and the film rejoined.
(iii) In order to avoid the above-described difficulties, photographic film to be processed is inspected to determine whether or not it has any torn-out portions, for instance, in a developing laboratory. If such is detected, these portions must be reinforced with an adhesive tape or the like prior to processing.
The reason why a conventional 35-mm photographic film suffers readily from this problem is that the TAC base has a low tearing strength.
In order to eliminate the above-described difficulties accompanying conventional photographic film, a film has been proposed in which a polyethyleneterephthalate (PET) base, which has as high tearing strength, is used as the film base. Merely by employing the PET base, the formation of the torn-out portions can be prevented. However, this film is disadvantageous in that a high force exerted on the film base will then act strongly on the film conveying unit in the camera or in the film processing machine, possibly resulting in damage thereto.
Accordingly, an object of the invention is to provide a 35-mm photographic film in which all of the above-described difficulties accompanying conventional 35-mm photographic film have been eliminated so that, in handling and processing the film, the film can be smoothly conveyed.